Divided We Fall
by RainTeaandDragons
Summary: It's not surprising that in all its complexity, it is family which drives a wedge between two of Fairy Tail's closest members. It is the eye of the storm, so to speak. Here Fairy Tail is faced with one of its most challenging trials, however this time it has come from within. In more ways than one, it will divide every heart the guild holds united.
1. Prologue

Hello :)  
So this is the prologue to my new Fairy Tail multi-chapter fic :) It is a Fairy Tail au inspired by the movie _Captain America: Civil War_ with the majority of it set after the current arc, as to who's who you'll have to wait and see! I plotted this out with multifandomdanny on tumblr, so this is a joint effort of sorts! :)

At this point there won't be any shipping, unless you want to read it like that, but I don't like to have things set in stone when I am writing from a planned plot so you never know :) however, there will be overloads of brotp moments, annnd (of course) angst. So I hope you like this little (very little) bit of set up before everything starts really happening next chapter! I'll be aiming to post every Friday, and if not, every second Friday but I'll see how I go :)

(also don't worry, the narration will go back to normal for future chapters)

Enjoy!

* * *

 **Prologue** **  
The Eye of the Storm**

Before we start this story, it is imperative you understand just how important some relationships are. So that as an extension of that, you can see how much love those relationships can hold. Friends, brothers, sisters, mothers, fathers…they all come down to one thing:

Family.

It is no coincidence that family, under its many definitions, is what makes this story possible. It's the eye of the storm, so to speak. It is this story's driving force. Without the perceived significance of family, there would be no reason for these events to have unfolded at all.

Now that we're on the same page, I can start. So bear with me as I take you back to the year X774, a time before our protagonists have even met…

If Gray had known what was to happen later that day, he most definitely wouldn't have taken an afternoon walk, nor would he have just simply waved his mum goodbye. The eight year old heard the demon before he saw it, and it haunted him for the rest of his life. The terrifying roar. The crunching of buildings underfoot. The screams. Gray had never felt fear like that before, and as the fear took hold, he ran. He ran to the only place he knew was safe, which _had_ to be safe. Home. To his family. _Mum_. _Dad_.

"Mum…Dad?"

The whisper was broken. Barely audible above the roars of the demon above as it lifted it's, massive clawed foot from the roof of Gray's home. The boy's eyes widened in shock as he took in the sight before him and an agonised scream left his lips. Gray darted forward on shaky legs before attempting to tear away the rubble of bricks glass and wood. Blood dripped from his stinging fingers as he tried in vain to clear the debris in the hopes of finding someone.

"DAAAAAD! MUUUUUM!"

As a nearby pile of debris exploded into flame Gray was thrown back into the burning grass. Anguished tears rolled down his cheeks as he tried to breathe through the thickening smoke. "MUM! DAD!"

"Gray?"

The voice was feint, barely a mumble but Gray knew, "Dad!" He crawled towards the noise, and pushing the crumbling bricks from his father's back he spoke again, "Dad!"

"Take this."

Gray felt as a familiar thick chain was pressed into his blood covered hands as he stared at his father through tear filled eyes.

"Run, Gray…run! Get to safety. Please…"

"Dad?" Gray whispered, "Dad!" A strangled scream was torn from Gray's lips as tears dripped from his chin to soak his shirt. Gray let out a sob as he looped the silver chain around his neck.

Gray only managed to stumble a few meters from the crumbling house before his shaking legs gave way beneath him. He crashed to the ground with a thud, as deep, rasping sobs shook his body. It wasn't long before the last of the collapsing building tumbled down around him. "Mum, Dad…" Hot tears rolled down Gray's cheeks as he felt the darkness pulling at his senses and he started to lose consciousness.

It was at this point that Gray realised that he didn't really care what happened to him. Everyone he cared about had been crushed by that destructive demon. He had no one left. No one at all.

 _My whole family is gone…_

Since that day Gray became a part of a number of families. Some big, some small, but each just as important as the other. Each leaving him with something more to hold on to, something more to care about. Each building him up to feel like he could be a better version of himself. In that way, family became his whole world again.

So from here I will leave you to make your own judgement on this story, but remember that for all involved, _family_ is the most important thing in their hearts.


	2. One - Small Fists

Hello! :) This chapter did take a bit longer to edit than planned! I am so sorry! I've had a pretty hectic week...but here we are :)

Enjoy!

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 **One – Small Fists**

Gramps and Erza watched the pair with matching amused expressions as the two young boys landed punch after punch on each other. The fight had started in the usual way: banter to blows. Erza felt like stopping them but the other knew there was no point. They would be back at each other's throats either way. She couldn't help but chuckle as she heard Gray's frustrated tone through the boy's panting.

"C'mon! Get up!"

Dark eyes glared down at his pink haired opponent, "You're the one who needs to get up! So you _come on_!"

Natsu shot Gray a haughty glare as he staggered to his feet. He aimed a punch at Gray but soon enough he found himself on the ground again.

"Sorry but you lose…" Gray turned to leave but he heard scuffling behind him.

"Hold on!" Natsu spoke defiantly. "This fight's not near over, Gray!"

"Well if that's the way you wan' it!" Gray grinned before charging towards Natsu with a yell.

"I'm not gonna lose!"

"Well you're gonna have to 'cause I wanna win!"

"You're going down!" The pair yelled in unison.

Small fists delivered blow after blow until they each landed simultaneous punches to the jaw sending both boys to the ground. They lay there panting, staring up at the deep blue sky.

\- o - o - o -

Gray waded through the water towards the massive clawed demon which towered over him, Natsu, and Lyon. _Deliora_. He had never expected to see that demon again, the demon which had taken everything from him. Yet here it was, and Gray knew there was only one thing that he could do at this point. He could feel his heart thudding painfully in his chest, even though he knew what he was doing was right. He wanted to finish that demon's tirade once and for all.

 _I'll be able to save everyone._

Gray took a deep breath, and just for a moment, before heading towards the demon, he glanced back.

 _If I do this they'll all be safe._

Natsu was still staring up at the demon with a mixture of awe and fear, while Lyon lay almost out cold on the rock beside him.

 _I'll give_ _ **my**_ _life to save_ _ **them**_ _._

"You've caused enough trouble; I'll clean up the mess you've made." Gray crossed over his arms in the spell's stance, "I'll seal the demon myself! ICED SHELL!" He could hear Lyon's panicked voice behind him but he ignored it.

"Don't do it Gray! Do you have any idea how long it took me to melt that ice? Sealing it again isn't going to stop me! I will not rest until I have defeated Deliora!"

"I can't worry about the future," Gray yelled as ice swirled around him, "I have to do this to stop it from killing us all right now!" His breath caught in his throat as a mop of pink hair pushed itself into his view. "Natsu…" _What is he doing!?_

"Why don't you let me handle this?"

"Don't be stupid!" Gray cried out, "Just get out of my way!"

 _Is he mad?_ "If I didn't let you do it before why would I let you do it now?" Natsu ignored Gray's request. "I'm not going to let you go out like that! Go ahead and cast the spell but I'm not moving."

 _Natsu…_ A pang of guilt gripped at Gray's chest soon enough it was drowned out by fear. He watched helplessly as Deliora's massive claw came hurtling towards Natsu's flame engulfed fist. "NATSSUUU!"

"I'm not giving up 'til the bitter end!"

The moment Natsu's clenched and flaming fist made contact with Deliora's the demon started to crack from head to toe. Gray stared in shock at the scene before him as Natsu stumbled back. He had no idea how Natsu had done what he'd done, but either way, relief flooded him knowing his friend was okay. _Thank you, Natsu._

\- o - o - o -

Natsu's eye's widened as he felt the strong vines wide around his chest and tighten so much that he could hardly move. He could only hear Sting and Rogue's yells as the head of the large carnivorous plant hurtled towards his trapped body. At the last second there was a flash of light as the whole of Mard Geer's plant froze on the spot.

 _Ice?_

Parts of the now shattered plant fell around him as his bindings cracked and Natsu fell to the ground. Moments later he felt a length of soft material fell around his shoulders and a frown creased his brows. "My scarf?"

"I found it."

Natsu glanced up in shock as the familiar voice reached his ears.

"If it's important to you don't lose it again." Gray frowned down at his friend, and was mildly surprised to see the wide eyed Dragon Slayer still staring at him in shock.

"Gray…" Natsu's jaw dropped.

"Gray!" Sting cried out.

"This magic…" Rogue's voice came out as barely a whisper as he stared around at the frozed vines.

"When did you…?" Natsu spoke in a broken whisper.

" _Who_ are you!?" Mard Geer growled.

"I'm the Devil Slayer who came here to defeat you." Gray glared at the demon before them.

They all stared at Gray incredulously as a tattoo formed on the Ice-Mage's arm.

"Devil Slayer, you say?"

"What the hell is that!?" Sting asked as he pulled Rogue into a more comfortable standing position.

"If Dragon Slaying Magic is for dragons, and God Slaying Magic is for gods, then…" Rogue deduced.

"This is magic that defeats demons." Gray clenched his fingers into a fist before running at Mard Geer and encasing him in a jagged piece of ice.

"This, is Silver's…" Mard Geer muttered from within the ice before he shattered it in one go. "I knew he would betray me one day. Though I didn't realise it would take this form. Fate is amusing indeed." He then sent a multitude of spiked vines at the group with a glint in his eyes.

With a swipe of his arm Gray instantly froze the vines in their tracks and they shattered before their eyes.

"He froze those thorns in an instant!" Rogue exclaimed.

"Incredible!" Sting agreed.

Mard Geer sent another lot of thorns which Gray froze again much to the demon's anger. Natsu watched with a mixture of amazement and fear as they exploded in a flash of light.

"You think fate is amusing? I don't think it's one damn bit amusing! For the sake of my old man's wish…"

 _Old man?_

"…I'll destroy all of you!" Gray yelled before sending jagged shards of ice at Mard Geer's chest.

The other three watched in shock as Mard Geer was thrown back only to land on his feet again.

"Die!" Gray yelled as he sprang towards the demon. "Ice Make Zero Sword!" He lashed forward only to find his path blocked by an incredibly muscled arm.

"Oh dear…it looks like I still don't have perfect control of my emotions."

"You're out of soldiers to protect you. I'm going to…"

"You're not ready yet. Do you really think that power will work on the true form of Mard Geer?" The demon drawled on as a bright glow started to surround him.

"His wounds…" Natsu whispered as he stared at the transforming demon.

"E.N.D. is going to awaken for the first time in 400 years…this is a good time for me to wake up as well." With that Mard Geer transformed into a clawed, bat like creature. At about twice his normal size he towered over Natsu and Gray. Flexing his fingers the demon folded out his wings. "My name is Mard Geer of Tartaros, King of the Underworld, an absolute demon."

Gray glared at the demon, as he raised his fist magical power swirled around it in an icy light. "Natsu…" He murmured.

"Yeah, I know." Natsu mirrored Gray's movements, his fist bursting into flames. "In the Name of Fairy Tail, we're going to take you down!"

The pair then dashed forward towards Mard Geer who was beginning to glow with a hot white light as he drew in his curse power. The demon then threw out his arms to send multitudes of sharp vines towards the two mages.

"Freeze!"

"Burn!"

While half the vines froze and shattered the other half burnt to a crisp as the full force of both different types of slayer magic hit the cursed plant. Then out of nowhere Mard Geer came hurtling towards the pair, clawed hands grasped both Natsu and Gray's heads to pull them up into the air. "This is the world on the other side of the underworld gate." He then flew straight towards the ground to pummel the mages into the hard ground. "I'm going to scrape away everything! Even your emotions…"

It was as if that was enough to pull the pair into action, they each grabbed the arm holding them hostage before using their combined power to shove Mard Geer into the dirt below. The demon then lifted them up again and smashed them into the ground. They staggered up only to have Mard Geer unleash a bolt of pure power at them making them skid backwards.

"Fire Dragon's Roar!" Natsu countered.

"Ice Demon's Rage!" Gray yelled.

Again a mixture of flames and ice went hurtling towards Mard Geer but they narrowly missed. This left the demon to shoot a thick, twisted knot of thorns towards the mages. With a chorused yell Gray and Natsu pummelled the vine until it exploded above them in a ball of bright white light.

"Ice Make Gungnir!" Gray yelled before shooting a bolt of ice towards the demon.

Mard Geer dodged but what he didn't expect was for Natsu to burst out of the ice.

"Fire Dragon's Brilliant Flame!" Natsu hit the demon head on with a ball of swirling fire, yet Mard Geer seemed hardly affected when he landed in front of them. "What is this guy, impenetrable?"

"Not if my magic hit's him…" Gray answered simply.

"You showed me a good time, human wizards." Mard Geer began. "Long ago, magic was born as one. Eventually, it developed into a great number of varieties. During that historical time, E.N.D. discovered a new possibility for magic. Curse power. The source of that power are curses, grudges, jealousy, hatred. All of those negative emotions become power, power based on the essence of life."

"What a load of crap." Natsu interrupted aggressively. "If that's the case then magic will create the future!"

Gray nodded in agreement as Mard Geer simply raised his hand to make a mottled black and blue cloud of power envelop Gray and Natsu where they stood.

"Wha- what is this?" Natsu gasped as the stuff completely surrounded them. "Fog? No…"

"My body!"

"I can't move!"

"Magic has no future. Curse Power is superior in regards to everything. Go to purgatory!" Mard Geer yelled, "This is the ultimate Curse Power that I devised to destroy Zeref! Memento Mori! To kill the immortalised Zeref the notion of life and death will be destroyed! Anyone hit by this Curse will be neither dead nor alive. They will just vanish."

Panic flooded Gray's body as the power surrounded him and he lost sight of Natsu completely. _Dammit!_ He could only hear Natsu's yells of pain and fear as he tried to move in the smog of the curse. Eventually as the darkness closed around him, part of Gray knew he was the only one who could save them this time. _The future..._

"Become nothing for eternity." Mard Geer watched as the dust cleared with a satisfied frown. "This is the ultimate Curse, Memento Mori."

Eventually the smoke cleared to reveal Gray standing in a protective stance in front of Natsu. Half his body was covered in strange black markings while the eye on that same side glowed purple.

"Gray?" Natsu whispered in shock. He hadn't expected them to be standing there at all, but Gray had protected them, Natsu didn't know what to think.

"It…can't be. Half of his body is demonic…" Mard Geer gasped. _Is that Silver's power?_ "Then he was protected against my ultimate Curse!?"

At that moment Gray wobbled where he stood, and Natsu watched in shock as Gray fell to the ground.

"In order to create the future all I can do is believe in Natsu."

"Gray…" Natsu whispered as he stared down at Gray's unmoving body. He didn't know whether his friend was dead or alive but as Mard Geer's voice reached his ears Natsu knew he had to do something. His anger and Gray's fall burned within him as he stared down at his friend.

"A mere human!?" Mard Geer screamed angrily.

"GRAYYY!" Natsu yelled as Mard Geer morphed into his demon form. "Dammit!" Natsu didn't even need to think as he felt Dragon Force take over. Mard Geer was going to regret ever considering doing something like that, especially after what the curse had done to Gray. The thought that Gray had sacrificed everything to save him was frightening, and it was that which drove the power of the next flaming punch to Mard Geer's stomach.

The demon was thrown back through wall after wall, the bricks crumbled on impact yet he still didn't stop. He couldn't stop the momentum. "What is this power?" Mard Geer groaned.

Natsu aimed another punch at the demon's jaw before his whole body burst into flames.

"Dragon Force?" Mard Geer whispered, his narrow eyes widening in shock.

"Inherited directly from Igneel!" Natsu yelled, "Dragon Slayer's Secret Art! Hidden Fire Form! Crimson Lotus Phoenix Blade!" With that Natsu pushed off from some debris to hurtle into the air, spinning directly towards Mard Geer in a spiral of flames. He hit him directly in the chest, sending them both flying. Almost immediately after the flames encasing his body faded, Natsu began to fall.

"It's not over!" Mard Geer raged before grabbing the falling Natsu by the collar. "I'm going to demolish every inch of your body!"

"I'm impressed…" Natsu whispered, a smug smile on his face. "My magic's at zero…"

"Die!"

"…but, I believe, too." Below him Natsu could see Gray staggering to his feet and relief flooded his warn out body. "GRAYYY!" Natsu yelled as he plummeted towards the ground.

In his hands Gray held a magnificent ice bow and arrow, and directing it at Mard Geer, he fired. "Ice Demon Zero's Destruction Bow!" Gray yelled as the arrow hurtled towards Mard Geer's chest. As the ice pierced the demon it expanded where it hit before exploding in a ball of bright white light.

Gray mirrored Natsu's wide grin as both the demon and the Dragon Slayer fell to the ground. _We did it. We defeated Mard Geer._

"You did it!" Natsu groaned as he pulled himself shakily to his feet. He watched Gray warily, worried that his friend might keel over again, but it seemed that for the moment Gray was still strong.

"No, it isn't over yet." Gray replied quietly. "I have to destroy E.N.D.."

\- o - o - o -

It wasn't long after the Alvarez war that for the second time Gray voiced to Natsu his plans to destroy E.N.D. but strangely enough it wasn't him who brought it up. The clean up after the war had taken a long time, but they had finally rebuilt the guild hall. The guild had lost count now as to the number of times they'd had to do that, but it didn't matter, as long as there was something there, someone there, the Fairy Tail Guild would stay strong.

The pair sat at the river which had long since dried up, but that spot was still the same as it had always been. A place where they could clear their heads, or where they could fight without destroying the guild hall.

"I am going to find Zeref." Natsu stated, "I need answers from him that I can't get anywhere else."

"I had a feeling you were going to say that." Gray replied grimly, "you do know how dangerous that could be for you right? I know he's your brother, but that doesn't mean he still won't try and kill you."

A dark chuckle left Natsu's lips, "True," he lied, _he won't kill me, not when I'm his only hope of dying himself._ "…but I still need answers."

"What if I said I wanted to find Zeref too? I still haven't destroyed the book of E.N.D. and I made a promise. I think the easiest way to find the book would be to find Zeref too, right?"

Natsu's heart sank, a memory surfaced of the fight with Mard Geer where Gray had said the exact same thing. At that point he hadn't known about _who_ E.N.D. was, but now he did. Part of him wanted to say something to Gray, the other was telling him to wait. "You could always come with me?"

Gray snorted. "With you?"

"I'm not too thrilled about it either Ice-Face," Natsu joked, "…but if we have the same goal then I don't see why not."

"Fine, let's set off tomorrow okay? The quicker this is over with the quicker things can get back to normal."

"Sure." Natsu grimaced, _this could be the worst idea ever, but I need to be able to keep an eye on him._

Gray let his mouth split into a wide grin, "What's the face for Flame-Brain?" He gave Natsu a gentle punch on his shoulder, "the prospect of traveling with me can't be _that_ bad…you are the one who asked after all!"

"It's nothing!" Natsu offered what he hoped was a suitable smile in return.

"C'mon." Gray pulled Natsu into a standing position and they headed off back to the guild. "Do you even know where to start to look?"

"How the hell would I know, Snowflake? Just cause Zeref's my brother that doesn't mean I have a psychic link with him or something!"

"Would be useful though."

"Shuddup!"

They continued to bicker all the way back to the guild, and though the atmosphere was lighter than it had been in quite a while Gray still felt like there was something slightly off about Natsu. Gray couldn't shake the feeling that his friend was hiding something from him. The niggling doubt sat at the back of his mind only to surface when he really didn't need it to. _There is something Natsu's not telling me, I know it._

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 **AN: Even though some of this chapter is a part of canon, those scenes were chosen carefully and each are important :) you can now maybe see a little of where this story is going!**


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